In a move that’s already angering U.S. lawmakers, the State Department said Wednesday that it would miss Congress’ March 17 deadline for declaring whether the Islamic State has carried out genocide against Christians and other minorities in Iraq and Syria.

State Department spokesman Mark Toner said the U.S. needs “additional time … in order to reach a more fact-based, evidence-based decision,” but would have an answer soon.

“Determining these kinds of legal definitions, such as genocide and crimes against humanity, requires a very detailed, rigorous legal analysis,” he told reporters at the daily press briefing.

Any Obama administration move to formally label the Islamic State’s organized violence against Christians, Yazidis, and other minorities — which has included torture, beheadings, crucifixions, and widespread sexual slavery — would take the ongoing debate over Syria to uncomfortable places for leaders in both parties.

That’s because using the G-word would provide fodder for lawmakers pushing for a more aggressive U.S. military intervention in the region — many of whom are Republicans. At the same time, such a declaration could give momentum to humanitarian advocates arguing for a more welcoming refugee policy — an issue touted more often by Democrats.

Regardless, a bipartisan push for a genocide declaration has been building in Congress for months as the death toll in Syria climbs to at least 270,000. Millions more have fled the country.

On Monday evening, the House voted 393-0 to declare the Islamic State’s attacks on religious minorities a genocide despite widespread disagreement about what consequences the designation should have for U.S. foreign policy. That followed approval of a budget measure months ago that called on Secretary of State John Kerry to inform Congress whether or not the Islamic State’s atrocities amounted to genocide by March 17.

In response to Wednesday’s delay, Rep. Chris Smith, the chairman of the global human rights subcommittee, told Foreign Policy that “Obama’s inability to lead and speak the truth about this genocide is another reason why our friends around the world doubt our resolve and our enemies see us as weak.”

The genocide debate has not become a focal point of the 2016 presidential contest, but both Hillary Clinton, the Democratic front-runner, and Sen. Marco Rubio, who dropped out of the Republican race on Tuesday, have used the term to describe the group’s attacks on minorities.

Republican anxiety over the treatment of Christians in Iraq and Syria has led some of them to propose controversial measures. Before leaving the race, former Florida Gov. Jeb Bush said the U.S. should allow in only Christian refugees, though he was visibly uncomfortable when pressed about how he would screen out non-Christians.

In addition to Bush, Texas Sen. Ted Cruz has proposed religious tests on refugees to screen out non-Christians.

After the House vote was approved Monday, powerful lawmakers like California Rep. Ed Royce, the chairman of the House Foreign Affairs Committee, urged the administration to make up its mind quickly.

“ISIS is guilty of genocide,” Royce said. “There is no reason for the administration to drag out its own genocide determination any longer.”

On Wednesday, Toner said that “everyone … around the world” was appalled by the Islamic State’s “horrific acts,” but noted that Kerry needed more time given the immense gravity and potential consequences of a genocide declaration.

“The secretary has urged his team here at the department, as well as the broader intelligence community and even the NGO community, to provide as much information and evidence as possible so that he can make the best decision possible,” Toner said. “And if this has delayed the process, we believe it’s worth it.”